A multipoint joint transmission technology is an important data transmission technology in LTE-A (Long Term Evolution Advanced, Long Term Evolution Advanced) and a future 5G network. The multipoint joint transmission technology means that multiple coordinated network devices that are geographically separate jointly transmit same data or jointly receive same data. In LTE-A, a typical multipoint joint transmission technology is a COMP (Coordinated MultiPoint transmission and reception, coordinated multipoint transmission/reception) technology. The COMP technology may be divided into an uplink COMP technology and a downlink COMP technology.
The downlink COMP, which is a downlink data packet processing mode, means that multiple coordinated network devices simultaneously transmit same data to user equipment. Specifically, a gateway or a main network device transmits a same data packet to the multiple coordinated network devices, and the coordinated network devices transmit the data packet to the user equipment. The coordinated network devices transmit the same data packet to the user equipment on a same time-frequency resource, and the user equipment combines same information transmitted by the coordinated network devices through different channels to obtain a diversity gain. Alternatively, after performing joint precoding, all of the coordinated network devices transmit the same data packet to the user equipment on a same time-frequency resource. The coordinated network devices effectively overcome interference between multiple users by using a precoding matrix, so as to improve data quality.
However, in a process in which the gateway or the main network device transmits the data packet to each coordinated network device, a data packet loss may be caused resulting from a cause such as network congestion or a transmission error. Therefore, the data packets sent by the coordinated network devices to the user equipment on the same time-frequency resource may be different, causing a data decoding error on the user equipment. For example, in a process in which two coordinated network devices obtain two data packets transmitted by the gateway or the main network device, resulting from a data packet loss, a first coordinated network device receives only a data packet 2, and a second coordinated network device receives a data packet 1 and the data packet 2. The first coordinated network device sends the data packet 2 to the user equipment, but the second coordinated network device sends the data packet 1 to the user equipment on a same time-frequency resource. Different coordinated network devices send different data packets to same user equipment on a same time-frequency resource, causing a data decoding error on the user equipment.